$result= mysql_query("
SELECT *
FROM medios_comunitarios
WHERE cod_mc IN (
SELECT cod_mc
FROM aspectos_legales
)
OR cod_mc IN (
SELECT cod_mc
FROM aspectos_sociales
)
OR cod_mc IN (
SELECT cod_mc
FROM aspectos_tecnicos
)
AND fecha Between '".$_SESSION['solicitud_desde']."'
AND '".$_SESSION['solicitud_hasta']."'
order by fecha"
, $link);